From: Radim Krčmář <rkrcmar@xxxxxxxxxx>
[ Upstream commit 0790ec172de1bd2e23f1dbd4925426b6cc3c1b72 ]
If EPT was enabled, unrestricted_guest was allowed in L1 regardless of
L0. L1 triple faulted when running L2 guest that required emulation.
Another side effect was 'WARN_ON_ONCE(vmx->nested.nested_run_pending)'
in L0's dmesg:
WARNING: CPU: 0 PID: 0 at arch/x86/kvm/vmx.c:9190 nested_vmx_vmexit+0x96e/0xb00 [kvm_intel] ()
Prevent this scenario by masking SECONDARY_EXEC_UNRESTRICTED_GUEST when
the host doesn't have it enabled.
Fixes: 78051e3b7e35 ("KVM: nVMX: Disable unrestricted mode if ept=0")
Cc: stable@xxxxxxxxxxxxxxx
Tested-By: Kashyap Chamarthy <kchamart@xxxxxxxxxx>
Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ed70394..47843b0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2381,8 +2381,7 @@ static __init void nested_vmx_setup_ctls_msrs(void)
if (enable_ept) {
/* nested EPT: emulate EPT also to L1 */
- nested_vmx_secondary_ctls_high |= SECONDARY_EXEC_ENABLE_EPT |
- SECONDARY_EXEC_UNRESTRICTED_GUEST;
+ nested_vmx_secondary_ctls_high |= SECONDARY_EXEC_ENABLE_EPT;
nested_vmx_ept_caps = VMX_EPT_PAGE_WALK_4_BIT |
VMX_EPTP_WB_BIT | VMX_EPT_2MB_PAGE_BIT |
VMX_EPT_INVEPT_BIT;
@@ -2396,6 +2395,10 @@ static __init void nested_vmx_setup_ctls_msrs(void)
} else
nested_vmx_ept_caps = 0;
+ if (enable_unrestricted_guest)
+ nested_vmx_secondary_ctls_high |=
+ SECONDARY_EXEC_UNRESTRICTED_GUEST;
+
/* miscellaneous data */
rdmsr(MSR_IA32_VMX_MISC, nested_vmx_misc_low, nested_vmx_misc_high);
nested_vmx_misc_low &= VMX_MISC_SAVE_EFER_LMA;
--
2.1.0
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